I suggest that you prepare a Child Support Worksheet and a Domestic Relations Financial Affidavit to take to your mediation. You will need to list your present income in both documents, as the amount of child support that you will have to pay will depend upon your present income and the mother's present income, as well as your childrens' expenses.
On your Domestic Relations Financial Affidavit, you will need to list all of your current living expenses and debts, so that your mediator can have an understanding of your budget, and work with you and the mother to reach an agreement on child support that you can meet.
Please know that this is a general interest posting and does not create an attorney-client relationship.
While the court system is intended to strive towards equity, the only individual's interest that gets taken into consideration is that of the child. It is on you to ensure that your own interests are protected.
As suggested, you should provide the mediator with as much information as possible, and prepare a child support worksheet prior to your mediation. I've provided a link to the GA worksheet (aka Child Support Calculator) below.
You can certainly prepare your own Child Support Worksheet from the DHR website to get an idea of what you should be paying based on your current income. Loss of employment is grounds to seek a modification.
As far as what to do or say in mediation ... that's legal advice, and no attorney on this site has sufficient information about your situation, or that of the other parent, to give you specific legal advice on this site. This is a big decision. You ought to consult with an attorney competent and experienced in Child Support to advise you in this matter.
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